The goal of this research is to determine the changes in chemical nature and metabolism of the nuclear proteins of the seminiferous epithelial cells of the testis of the rat during spermatogenesis and spermiogenesis and to ultilize such information in developing new methods of contraception. Further refinements will be made in our procedure for the separation of the nuclei of seminiferous epithelial cells by centrifugation through sucrose density gradients. The purification and characterization of the protamines of the sperm heads of the rat and the bull will be completed. The "unusual" histones of rat testis will be isolated, purified, and characterized. The possible uncoupling of histone and DNA synthesis in meiosis will be examined. A study will be made of the role of hormones (FSH, LH, testosterone, and prostaglandins) in the synthesis, acetylation, and phosphorylation of histones, protamines and other chromosomal proteins in various stages of spermatogenesis. Various inhibitors will be studied to determine their effects upon the synthesis, acetylation, and phosphorylation of chromosomal proteins during spermatogenesis.